Boko Haram militants killed scores of residents of the Damasak town in Borno State on Monday, in a third major attack in the region in a week.
The gunmen stormed into the Nigeria-Niger border town early on Monday and set houses on fire with petrol bombs and improvised explosive devices (IEDs), forcing locals to flee across the border into Niger.
"The insurgents came at about 9.00 am and fired shots into houses to force people out. They are still there up till now and still firing shots. Many people may have died. I am talking to you now from the bush," witness Bukar Aji told Reuters.
While the exact number of people killed in the latest Boko Haram attack was not known, at least 15 people were said to have drowned while trying to cross a river to escape the militants.
This was said to be a reprisal attack by the terror group after its failed attempt to raid the town last week. Some accounts suggest that the gunmen disguised themselves as traders and then opened fire at a market in Damasak.
"The terrorists disguised as traders and opened fire on unsuspecting traders at a market in Damasak," a military officer told AFP, according to The News, a Nigerian media.
"They pretended to be traders but sadly inflicted horror. Many traders escaped with bullet wounds while many are lying dead at the market," another witness said.
Boko Haram had killed 48 fishermen last Thursday near the Nigerian border with Chad, and a day before that the Islamist militants attacked the village of Azaya Kuram in Borno state, killing at least 45 people.
Borno state has been under a state of emergency owing to the rising insurgency of the Islamist Boko Haram group.